# Kotlin OTP

This library provides various [Pseudorandom Number Generator](https://en.wikipedia.org/wiki/Pseudorandom_number_generator)
implementations in Kotlin Multiplatform.

## Features

* Generate random numbers using Kotlin's Random interface.
* Seed the PRNGs to receive predictable results.
* Reseed the PRNGs to add entropy to the following results.
* [HMAC DRBG](https://en.wikipedia.org/wiki/NIST_SP_800-90A#Hash_DRBG_and_HMAC_DRBG)
* Multiplatform support
    * JVM
    * JavaScript
    * Native (Linux)

## Installation

Add the following to your `build.gradle.kts`.

```kotlin
repositories {
    maven("https://git.infendro.com/api/packages/Infendro/maven")
}

dependencies {
    implementation("com.infendro:random:1.0.0")
}
```

## Usage

```kotlin
import com.infendro.hash.SHA256
import com.infendro.random.PRNG

fun main() {
    // create a PRNG instance
    val rng = PRNG.HMAC(SHA256)

    // seed the PRNG to receive predictable results
    rng.seed(/* some seed */)
    val a = rng.nextInt()
    val b = rng.nextInt()
    val c = rng.nextInt()

    // reseed the PRNG to add entropy to the following results
    rng.reseed(/* some random entropy */)
    val d = rng.nextInt()
    val e = rng.nextInt()
    val f = rng.nextInt()

    // each run:
    // a, b, and c will be predictable
    // d, e, and f will be random (assuming the entropy is also random)
}
```